Wired circuit board assembly sheet

ABSTRACT

A wired circuit board assembly sheet has a plurality of wired circuit boards, distinguishing marks for distinguishing defectiveness of the wired circuit boards, and a supporting sheet for supporting the plurality of wired circuit boards and the distinguishing marks. Each of the distinguishing marks has an indication portion for indicating a specified one of the wired circuit boards.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2006-111163 filed on Apr. 13, 2006, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wired circuit board assembly sheet inwhich a plurality of wired circuit boards are formed.

2. Description of Related Art

A wired circuit board typically comprises an insulating base layer, aconductive pattern formed on the insulating base layer, and aninsulating cover layer formed on the insulating base layer to cover theconductive pattern. Such a wired circuit board is produced as a wiredcircuit board assembly sheet in which, e.g., a plurality of wiredcircuit boards are formed on a single metal supporting board.

More specifically, in the production of the wired circuit board assemblysheet, the insulating base layer, the conductive pattern, and theinsulating cover layer are successively formed in an aligned state onthe single metal supporting board to correspond to each of theindividual wired circuit boards. Then, the metal supporting board ispartially cut out such that the cut-out portion corresponds to an outershape of each wired circuit board, whereby each of the wired circuitboards and the supporting sheet for supporting each wired circuit boardare formed. In this manner, the wired circuit boards are produced as thewired circuit board assembly sheet in which the plurality of wiredcircuit boards are provided in an aligned state on the single metalsupporting board.

Then, each of the wired circuit boards is appropriately cut away fromthe wired circuit board assembly sheet described above for wide use invarious electric equipment and electronic equipment.

In such a wired circuit board assembly sheet, it has been known toprovide a defectiveness distinguishing mark corresponding to each wiredcircuit board for distinguishing defectiveness.

For example, it has been proposed to distinguish whether a circuit boardis defective or not by removing an alignment mark serving as a referencefor aligning an electronic component or the like with laser processingto recognize the presence or absence of the alignment mark using anautomatic image recognition device (see, e.g., Japanese UnexaminedPatent Publication No. 2001-127399).

SUMMARY OF THE INVENTION

In the wired circuit boards disclosed in Japanese Unexamined PatentPublication No. 2001-127399, a circular alignment mark is formed on thecorner portion of a wired circuit board region in which the wiredcircuit board is formed.

To improve the productivity of the wired circuit board and reduce theproduction cost thereof, it is necessary to arrange the wired circuitboards at a high density in a single wired circuit board assembly sheet.However, in the wired circuit board assembly sheet in which the wiredcircuit boards are arranged at a high density, the region in which thedefect-distinguishing mark can be formed is small so that the pluralityof wired circuit boards are in close proximity to one of thedefect-distinguishing marks. In such a case of the circular alignmentmarks disclosed in Japanese Unexamined Patent Publication No.2001-127399, it is difficult to identify the wired circuit board towhich each alignment mark corresponds.

It is therefore an object of the present invention to provide a wiredcircuit board assembly sheet in which, when the defectiveness of thewired circuit board is distinguished, the wired circuit boardcorresponding to each of the distinguishing marks can be easilyidentified.

A wired circuit board assembly sheet according to the present inventioncomprises a plurality of wired circuit boards, distinguishing marks fordistinguishing defectiveness of the wired circuit boards, and asupporting sheet for supporting the plurality of wired circuit boardsand the distinguishing marks, wherein each of the distinguishing markscomprises an indication portion for indicating a specified wired circuitboards.

In the wired circuit board assembly sheet according to the presentinvention, each of the distinguishing marks for distinguishingdefectiveness of the wired circuit boards comprises the indicationportion for indicating the specified wired circuit board. Accordingly,when the distinguishing marks are formed in the wired circuit boardassembly sheet, it is possible to distinctly represent thecorrespondence between the distinguishing mark and the specified wiredcircuit board by directing the indication direction of the indicationportion toward the specified wired circuit board. As a result, even whenthe density of the wired circuit boards is high and the plurality ofwired circuit boards are in close proximity to one of the distinguishingmarks, or the plurality of distinguishing marks are adjacent to eachother, the wired circuit board corresponding to each of thedistinguishing marks can be easily identified.

In the wired circuit board assembly sheet according to the presentinvention, it is preferable that each of the distinguishing marks isformed in a non-point-symmetrical shape.

When each of the distinguishing marks has a non-point-symmetrical shape,even in the case where the distinguishing mark is formed with aplurality of portions (quasi-indication portions) which can function asthe indication portions, it is possible to prevent directions(quasi-indication directions) which may possibly be the respectiveindication directions of the quasi-indication portions from overlappingon the same straight line. Accordingly, even when the two wired circuitboards are formed in adjacent relation to the distinguishing mark, it ispossible to prevent each of the quasi-indication directions from beingdirected toward a direction reverse to the indication direction. As aresult, it is less likely to misidentify the specified wired circuitboard corresponding to each of the distinguishing marks as another wiredcircuit board. This makes it possible to easily and reliably identifythe wired circuit board corresponding to each of the distinguishingmarks.

In the wired circuit board assembly sheet according to the presentinvention, it is preferable that the indication portion has a shapetapered toward an indication direction indicating the specified wiredcircuit board.

When each of the indication portions has a shape tapered toward theindication direction indicating the specified wired circuit board, theindication portion can distinctly represent the indication direction.This allows easy identification of the wired circuit board correspondingto each of the distinguishing marks.

In the wired circuit board assembly sheet according to the presentinvention, it is preferable that each of the distinguishing marks has agenerally polygonal shape having an odd number of angles.

When each of the distinguishing marks has a generally polygonal shapehaving an odd number of angles, it is possible to use an arbitraryportion including any of the angles as the indication portion andindicate the specified wired circuit board with the indication portion.In addition, because each of the distinguishing marks has a generallypolygonal simple shape, the distinguishing marks can be formed easily.

In the wired circuit board assembly sheet according to the presentinvention, it is preferable that the distinguishing marks are arrangedin mutually adjacent relation and the indication portions of thedistinguishing marks arranged in adjacent relation have respectiveindication directions different from each other.

When the distinguishing marks are arranged in mutually adjacent relationand the indication portions of the distinguishing marks have therespective indication directions different from each other, it is lesslikely to confuse, in identifying the wired circuit board correspondingto each of the distinguishing marks, the corresponding wired circuitboard with another wired circuit board. This allows easy identificationof the wired circuit board corresponding to each of the distinguishingmarks.

In the wired circuit board assembly sheet according to the presentinvention, it is preferable that the supporting sheet has openingsformed in the portions where the distinguishing marks are formed andeach of the distinguishing marks comprises a removal portion disposed inthe opening for indicating whether the corresponding wired circuit boardis defective or non-defective; and a joint portion made of a resin forjointing the removal portion to the supporting sheet.

When the supporting sheet has the openings formed in the portions wherethe distinguishing marks are formed and each of the distinguishing markscomprises the removal portion for indicating whether the correspondingwired circuit board is defective or non-defective and the joint portionmade of a resin for jointing the removal portion to the supportingsheet, the removal portion can be easily removed from the supportingsheet by cutting the joint portion to show whether the wired circuitboard is defective or non-defective. Because the joint portion is madeof a resin, there is no production of metal powder or the like even whenthe joint portion is cut so that the wired circuit board is allowed toretain its excellent electric characteristics. Even when punching isperformed with a stamping die, the abrasion of the stamping die can bereduced. As a result, it is possible to easily and reliably remove theremoval portion to provide the wired circuit board with high connectionreliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a wired circuit board assembly sheetaccording to an embodiment of the present invention;

FIG. 2 is a plan view of a wired circuit board shown in FIG. 1;

FIG. 3 is a bottom view showing a placement of a metal supporting layerin the wire circuit board shown in FIG. 2;

FIG. 4 is a cross-sectional view taken along the line A-A of the wirecircuit board assembly sheet shown in FIG. 1;

FIG. 5 is an enlarged plan view of a distinguishing mark formationregion formed in the wired circuit board assembly sheet shown in FIG. 1;

FIG. 6 is a process step diagram showing the steps of producing thewired circuit board assembly sheet,

(a) showing the step of preparing a metal supporting board,

(b) showing the step of forming a plurality of insulating base layers onthe metal supporting board,

(c) showing the step of forming a conductive pattern on the insulatingbase layer of each of the wired circuit boards and forming a markformation portion on the insulating base layer of each distinguishingmarks, and

(d) showing the step of forming insulating cover layers on therespective insulating base layers;

FIG. 7 is a process step diagram showing, subsequently to FIG. 6, thesteps of producing the wired circuit board assembly sheet,

(e) showing the step of forming an etching resist over the entiresurface of the wired circuit board assembly sheet in the midway ofproduction process and forming the etching resist in a predeterminedpattern on the back surface thereof,

(f) showing the step of opening the metal supporting board exposed fromthe etching resist by etching, and

(g) showing the step of removing the etching resist;

FIG. 8 is a plan view showing a wired circuit board assembly sheetaccording to other embodiments of the present invention,

(a) showing the distinguishing marks each having an equilaterallypentagonal shape when viewed in plan view,

(b) showing the distinguishing marks each having a generally pentagonalshape when viewed in plan view (in the shape of a home plate),

(c) showing the distinguishing marks each having an equilaterallyheptagonal shape when viewed in plan view, and

(d) showing the distinguishing marks each having a generally heptagonalshape when viewed in plan view; and

FIG. 9 is a plan view showing a wired circuit board assembly sheetaccording to still other embodiments of the present invention,

(e) showing the distinguishing marks each having an arrow-like shapewhen viewed in plan view,

(f) showing the distinguishing marks each having a convex shape whenviewed in plan view, and

(g) showing the distinguishing marks each having a sectorial shape whenviewed in plan view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a plan view showing a wired circuit board assembly sheetaccording to an embodiment of the present invention. FIG. 2 is a planview of one of the wired circuit boards shown in FIG. 1. FIG. 3 is abottom view showing a placement of a metal supporting layer in the wirecircuit board shown in FIG. 2. FIG. 4 is a cross-sectional view takenalong the line A-A of the wire circuit board assembly sheet shown inFIG. 1. FIG. 5 is an enlarged plan view of a distinguishing markformation region formed in the wired circuit board assembly sheet shownin FIG. 1. In FIG. 1, an insulating base layer 16 and an insulatingcover layer 18, described later are omitted.

In FIG. 1, a wired circuit board assembly sheet 1 comprises a pluralityof wired circuit boards 2, distinguishing marks 3, and a supportingsheet 4 for supporting the plurality of wired circuit boards 2 and thedistinguishing marks 3.

In the supporting sheet 4, the respective wired circuit boards 2 areprovided in pairs. More specifically, the pair of the wired circuitboards 2 includes one wired circuit board 2 a formed at a relativelyupper position and the other wired circuit board 2 b formed at arelatively lower position, each placed in mutually spaced-apart facingrelation in the vertical direction of FIG. 1. The pairs of the wiredcircuit boards 2 are arranged in mutually spaced-apart aligned relationand supported by the supporting sheet 4 via cuttable supporting portions5. In the following description, for the purpose of identification, eachof the components of the one wired circuit board 2 a is denoted byadding “a” at the end of a reference numeral, while each of thecomponents of the other wired circuit board 2 b is denoted by adding “b”at the end of a reference numeral.

In FIG. 2, the wired circuit board 2 is a flexible wired circuit boardformed in a generally U-shape when viewed in plan view, which integrallycomprises a first connecting portion 6 for connecting to a connector orthe like, a second connecting portion 7 for connecting to an externalterminal or the like, and a flat-plate wiring portion 8 coupling thefirst connecting portion 6 to the second connecting portion 7.

The first connecting portion 6 has a generally rectangular shape whenviewed in plan view and comprises a terminal region 9 formed on arelatively upper side in the vertical direction of FIG. 2, a wiringregion 10 disposed below the terminal region 9 in facing relationthereto, and a coupling region 11 for coupling the terminal region 9 tothe wiring region 10 extending from the widthwise left end portion ofthe first connecting portion 6 to the generally middle portion thereof.The portion between the terminal region 9 and the wiring region 10 ofthe first connecting portion 6 extending from the generally middleportion to the right end portion in the widthwise direction thereof,i.e., the portion in which the coupling region 11 is not formed isformed as a groove region 12.

The terminal region 9 has a first terminal portion 14 formed with aplurality of first terminals 20 (described later) each electricallyconnected to a connector or the like. The first terminal portion 14 isprovided in the shape of an elongated rectangle when viewed in plan viewat the rear end portion (front and rear sides respectively correspond toone side and the other side in a direction in which wires 22 describedlater extend) of the terminal region 9 along the widthwise direction(widthwise direction corresponds to a direction orthogonal to theextending direction (front-to-rear direction) of the wires 22 describedlater).

The second connecting portion 7 is formed in a generally rectangularshape of which the front end portion is tapered and comprises secondterminal portions 15 formed with a plurality of second terminals 21(described later) each electrically connected to an external circuit orthe like. The second terminal portions 15 are provided on the both sideend portions in the widthwise direction of the second connecting portion7 along the front-to-rear direction. The second connecting portion 7 hasa fixing hole 13 formed in the front end portion thereof to extendtherethrough.

The flat-plate wiring portion 8 has a generally L-shape when viewed inplan view and is provided between the widthwise left end of the firstconnecting portion 6 (wiring region 10) and the rear end of the secondconnecting portion 7 to couple therebetween.

As shown in FIG. 4, the wired circuit board 2 also comprises aninsulating base layer 16, a conductive pattern 17 formed on the surfaceof the insulating base layer 16, and an insulating cover layer 18 formedon the insulating base layer 16 to cover the surface of the conductivepattern 17. In addition, the wired circuit board 2 comprises a metalsupporting layer 19 partially formed on the back surface of theinsulating base layer 16 (see FIG. 3).

As shown in FIG. 2, the insulating base layer 16 is formed in a patternhaving the basic shape of the wired circuit board 2, i.e., a generallyU-shape when viewed in plan view.

The insulating base layer 16 is formed of a film of a synthetic resinsuch as, e.g., a polyimide resin, an acrylic resin, a polyether nitrileresin, a polyether sulfone resin, a polyethylene terephthalate resin, apolyethylene naphthalate resin, or a polyvinyl chloride resin. As thesynthetic resin, a photosensitive synthetic resin is preferably used, ormore preferably a photosensitive polyimide resin is used.

The thickness of the insulating base layer 16 is in the range of, e.g.,5 to 25 μm, or preferably 7 to 15 μm.

As shown in FIG. 2, the conductive pattern 17 is formed continuouslyover the first connecting portion 6, the flat-plate wiring portion 8,and the second connecting portion 7. The conductive pattern 17integrally comprises the plurality of first terminals 20, the pluralityof second terminals 21, and the plurality of wires 22 connecting thefirst terminals 20 and the second terminals 21 respectively.

Each of the first terminals 20 is in the form of a quadrilateral landand provided on the first terminal portion 14 of the first connectingportion 6 (terminal region 9) in mutually spaced-apart relation alongthe widthwise direction. Each of the first terminals 20 is not limitedto the quadrilateral land and may also be a round land.

Each of the second terminals 21 is in the form of a quadrilateral landand provided on each of the second terminal portions 15 provided on theboth side end portions in the widthwise direction of the secondconnecting portion 7 in mutually spaced-apart relation along thefront-to-rear direction. Each of the second terminals 21 is not limitedto the quadrilateral land and may also be a round land.

The wires 22 are arranged over the first connecting portion 6, theflat-plate wiring portion 8, and the second connecting portion 7 inmutually spaced-apart parallel relation in the widthwise direction. Thewires 22 are provided to individually connect the first terminals 20 tothe second terminals 21, respectively.

The conductive pattern 17 is formed of a conductive foil (metal foil)made of, e.g., copper, nickel, gold, a solder, an alloy thereof, or thelike. In terms of conductivity, inexpensiveness, and workability, acopper foil is preferably used.

The conductive pattern 17 has a thickness in the range of, e.g., 5 to 35μm, or preferably 7 to 18 μm. Each of the wires 22 has a width in therange of, e.g. 25 to 150 μm, or preferably 30 to 100 μm at theflat-plate wiring portion 8. The spacing between the wires 22 is in therange of, e.g., 25 to 150 μm, or preferably 30 to 100 μm at theflat-plate wiring portion 8.

The insulating cover layer 18 is formed in a pattern having asubstantially identical shape to the insulating base layer 16.

The insulating cover layer 18 has openings formed to expose the firstterminals 20 and the second terminals 21. These opening portions formthe first terminal portions 14 and the second terminal portions 15.

For the insulating cover layer 18, a film of a synthetic resin, which isthe same for the insulating base layer 16 described above, is used. Asthe synthetic resin, a photosensitive polyimide resin is preferablyused. The thickness of the insulating cover layer 18 is in the range of,e.g., 3 to 25 μm, or preferably 4 to 15 μm.

The metal supporting layer 19 is formed of a metal supporting board 45(see FIG. 6( a)) together with the supporting sheet 4 described later.As shown in FIG. 3, the metal supporting layer 19 is formed of separatethin plates at the first connecting portion 6 (terminal region 9 andwiring region 10), at the flat-plate wiring portion 8, and at the secondconnecting portion 7.

At the first connecting portion 6, the metal supporting layer 19 isprovided on the back surface of the insulating base layer 16 to serve asa first reinforcing plate 23 for reinforcing the terminal region 9formed with the first terminal portions 14 and as a second reinforcingplate 24 for reinforcing the wiring region 10. At the second connectingportion 7, the metal supporting layer 19 is provided over the entireback surface of the insulating base layer 16 of the second connectingportion 7 to serve as a third reinforcing plate 25 for reinforcing thesecond terminal portions 15. At the flat-plate wiring portion 8, themetal supporting layer 19 is provided at the bent portion of theflat-wire surface 8 on the back surface of the insulating base layer 16in a generally L-shape to serve as a generally rectangular fourthreinforcing plate 26 for reinforcing the bent portion.

In the wired circuit board 2, by thus placing the metal supporting layer19, flexibility is imparted to the region (coupling region 11) betweenthe terminal region 9 and the wiring region 10 in the first connectingportion 6, to the region between the first connecting portion 6 and thebent portion of the flat-plate wiring portion 8, and to the regionbetween the second connecting portion 7 and the bent portion of theflat-plate wiring portion 8.

The metal supporting layer 19 is formed of a sheet of a metal such as,e.g., stainless steel, 42-alloy, or copper. As the metal, stainlesssteel is preferably used. The thickness of the metal supporting layer 19is in the range of, e.g., 25 to 200 μm, or preferably 50 to 100 μm.

As shown in FIGS. 1 and 4, the supporting sheet 4 is formed togetherwith each of supporting portions 5 and each of the metal supportinglayers 19 by partially cutting out the metal supporting board 45 (seeFIGS. 6 and 7) such that the cut-out portions correspond to therespective outer configurations of the wired circuit boards 2 in amethod for producing the wired circuit board assembly sheet 1 describedlater.

The supporting sheet 4 has clearance grooves 27 between the innerperipheral portions of the supporting sheet 4 surrounding the individualwired circuit boards 2 and the respective outer peripheral portions ofthe wired circuit boards 2, which are formed in generally frame-likeshapes when viewed in plan view to surround the individual wired circuitboards 2. The width of each of the clearance grooves 27 is normally setin the range of 0.5 to 1.0 mm.

The supporting sheet 4 also has the plurality of supporting portions 5formed to traverse the clearance grooves 27. Each of the supportingportions 5 is in a generally rectangular shape when viewed in plan viewand formed to extend from the inner peripheral portion of the supportingsheet 4, orthogonally pass over the clearance groove 27, and reach theouter peripheral portion of the wired circuit board 2. The width of thesupporting portions 5 is normally set in the range of 0.2 to 2.0 μm, orpreferably 0.3 to 1.0 μm. The number of the supporting portions 5 andthe positions thereof at which they are formed can be determinedappropriately in accordance with the size, shape, and the like of thewired circuit board 2.

The supporting sheet 4 has a distinguishing mark formation region 28formed on which the distinguishing marks 3 are provided.

The distinguishing mark formation region 28 is provided in one-to-onerelation to one pair of the wired circuit boards 2 (the one wiredcircuit board 2 a and the other wired circuit board 2 b) arranged infacing relation such to interpose between the one wired circuit board 2a and the other wired circuit board 2 b. As shown in FIG. 5, thedistinguishing mark formation region 28 is formed with two openings 29,more specifically the one opening 29 a on the left-hand side in thelateral direction of each of FIGS. 1 and 5 and the other opening 29 b onthe right-hand side in the lateral direction.

The opening 29 is in a generally equilaterally triangular shape withcurved angles when viewed in plan view and formed to extend through thesupporting sheet 4 in the thickness direction. Specifically, the opening29 is formed such that an indication vertex 30 a, which is an arbitraryangle of the one opening 29 a, faces the one wired circuit board 2 a andthat an indication vertex 30 b, which is an arbitrary angle of the otheropening 29 b, faces the other wired circuit board 2 b. One side (linearportion) of the opening 29 has a length set to, e.g., 400 μm, orpreferably 200 μm.

The distinguishing mark 3 is for distinguishing defectiveness of thewired circuit board 2. The distinguishing mark 3 is provided as onedistinguishing mark 3 a and the other distinguishing mark 3 b in thedistinguishing mark formation region 28, specifically providedrespectively in the one opening 29 a and the other opening 29 b. In thefollowing description, for the purpose of identification, each of thecomponents of the one distinguishing mark 3 a is denoted by adding “a”at the end of a reference numeral, while each of the components of theother distinguishing mark 3 b is denoted by adding “b” at the end of areference numeral.

The distinguishing mark 3 comprises a removal portion 31, an outer frameportion 32, and joint portions 33.

The removal portion 31 is for indicating that the corresponding wiredcircuit board 2 is non-defective and disposed generally at the center ofthe opening 29. When viewed in plan view, the removal portion 31 isformed in a generally equilaterally hexagonal shape having curvedangles, which is slightly smaller in size than the opening 29.

As shown in FIG. 4, the removal portion 31 comprises a metal supportinglayer 19, an insulating base layer 16 formed on the metal supportinglayer 19, a mark formation portion 34 formed on the insulating baselayer 16, and an insulating cover layer 18 formed on the insulating baselayer 16 to cover a part of the mark formation portion 34.

As shown in FIG. 5, the metal supporting layer 19 of the removal portion31 is formed in a shape corresponding to the outer shape of the removalportion 31, i.e., the generally equilaterally hexagonal shape havingcurved angles.

The insulating base layer 16 of the removal portion 31 is formed on themetal supporting layer 19 to have a generally equilaterally hexagonalshape having curved angles when viewed in plan view, which is generallyanalogous to and slightly smaller in size than the metal supportinglayer 19. As a result, the peripheral end portion 36 of the metalsupporting layer 19 is exposed from an insulating-base-layer outerperipheral surface 35, which is the outer peripheral surface of theinsulating base layer 16, except for the joint portions 33 describedlater.

The mark formation portion 34 is formed on the insulating base layer 16to have a generally equilaterally hexagonal shape having curved angleswhen viewed in plan view, which is generally analogous to and slightlysmaller in size than the insulating base layer 16. The mark formationportion 34 has a non-defective mark 38 provided integrally at the centerthereof when viewed in plan view and exposed from aninsulating-cover-layer opening 37 described later. On the surface of thenon-defective mark 38, a metal plating layer (not shown) made of gold orthe like is formed. In the distinguishing mark 3, a direction from thecenter of the non-defective mark 38 toward the indication vertex 30 isan indication direction.

As shown in FIG. 4, the insulating cover layer 18 of the removal portion31 is formed on the insulating base layer 16 to cover the mark formationportion 34 and expose the non-defective mark 38. As shown in FIG. 5, theinsulating cover layer 18 is formed to have a generally equilateralhexagonal shape having curved angles when viewed in plan view, which isa generally identical shape of the insulating base layer 16. As aresult, the peripheral end portion 36 of the metal supporting layer 19is exposed from an insulating-cover-layer outer peripheral surface 39,which is the outer peripheral surface of the insulating cover layer 18,except for the joint portions 33.

The insulating cover layer 18 has the insulating-cover-layer opening 37formed in a circular shape at the center thereof when viewed in planview to expose the non-defective mark 38 from the insulating cover layer18.

In the removal portion 31, the length of one side (linear portion) ofthe metal supporting layer 19 is set to e.g., 1000 μm, or preferably 600μm. The length of one side (linear portion) of each of the insulatingbase layer 16 and the insulating cover layer 18 is set to e.g., 800 μm,or preferably 550 μm. The length of one side (linear portion) of themark formation portion 34 is set to e.g., 750 μm, or preferably 500 μm.The diameter of the non-defective mark 38 is set to e.g., 750 μm, orpreferably 500 μm. The margin (spacing between the end surface of theperipheral end portion 36 of the metal supporting layer 19 and each ofthe insulating-base-layer outer peripheral surface 35 and theinsulating-cover-layer outer peripheral surface 39) in the exposedperipheral end portion 36 of the metal supporting layer 19 is set toe.g., 100 μm, or preferably 50 μm.

As shown in FIG. 5, the outer frame portion 32 is provided in acircumferentially continuous belt-like shape to surround the opening 29in the supporting sheet 4. The outer frame portion 32 is formed in agenerally equilaterally triangular shape having curved angles whenviewed in plan view. The outer frame portion 32 exposes the openingperipheral end portion 40 of the supporting sheet 4 except for the jointportions 33. As shown in FIG. 4, the outer frame portion 32 is formed ofthe insulating base layer 16 and the insulating cover layer 18.

The insulating base layer 16 of the outer frame portion 32 is formed tocorrespond to the outer shape of the outer frame portion 32.

The insulating cover layer 18 of the outer frame portion 32 is formed onthe insulating base layer 16 to have the same shape as the insulatingbase layer 16.

The width of the outer frame portion 32 in a direction orthogonal to thecircumferential direction thereof is set to e.g., 150 μm, or preferably100 μm. The margin (spacing between the inner peripheral surface of theouter frame portion 32 and the peripheral end surface of the openingperipheral end portion 40) of the exposed opening peripheral end portion40 is set to e.g., 100 μm, or preferably 50 μm.

As shown in FIG. 5, the joint portions 33 are provided between therespective middles of the three sides of each of the removal portions 31out of six sides which face the respective sides of the correspondingouter frame portion 32 and the middles of the three sides of the outerframe portion 32 to couple the removal portion 31 to the supportingsheet 4.

The joint portions 33 are arranged radially around the non-defectivemark 38 of the removal portion 31 and, more specifically arranged suchthat each angle formed between any two adjacent joint portions 33 is 120degrees when viewed in plan view. Each of the joint portions 33 isformed to traverse the corresponding opening 29 from the removal portion31 in a direction orthogonal to the circumferential direction of theopening 29 and extend between the removal portion 31 and the outer frameportion 32.

Each of the joint portions 33 is formed of the insulating base layer 16and the insulating cover layer 18 and provided continuously from therespective insulating base layer 16 and insulating cover layer 18 of theremoval portion 31 and the outer frame portion 32 respectively.

The joint portion 33 comprises a removal-portion-side end portion 41connected to the removal portion 31, a supporting-sheet-side end portion42 connected to the supporting sheet 4, and a joint middle portion 43connected therebetween.

The removal portion-side end portion 41 is formed having a curved partwhich is gradually curved from the joint middle portion 43 toward theremoval portion 31 to increase in width to form a wider skirt part.

The supporting-sheet-side end portion 42 is formed having a curved partwhich is gradually curved from the joint middle portion 43 toward theouter frame portion 32 to increase in width to form a wider skirt part.

The joint middle portion 43 is formed integrally and continuously withthe removal-portion-side end portion 41 and the supporting-sheet-sideend portion 42 to have a flat belt-like shape having the same widthextending between the removal-portion-side end portion 41 and thesupporting-sheet-side end portion 42.

The insulating base layer 16 of the joint portion 33 is formed tocorrespond to the outer shape of the joint portion 33.

The insulating cover layer 18 of the joint portion 33 is formed on theinsulating base layer 16 to have the same shape as the insulating baselayer 16.

The width of the joint portion 33 in a direction orthogonal to thelongitudinal direction of the joint middle portion 43 is set to e.g.,500 μm, or preferably 300 μm. The maximum width of the joint portion 33at the removal-portion-side end portion 41 and the supporting-sheet-sideend portion 42 is set to e.g., 100 μm, or preferably 60 μm.

In the distinguishing mark 3, the region surrounded by the curved partof the outer frame portion 32 having a generally V-shape when viewed inplan view and surrounding the indication vertex 30, by the two jointportions 33 continued to the both ends of the curved part, and by theremoval portion 31 interposed between the two joint portions 33 forms anindication region 44 as an indication portion. The indication region 44is formed in a tapered shape in the indication direction indicating thecorresponding wired circuit board 2.

FIGS. 6 and 7 are process step diagrams showing the steps of producingthe wired circuit board assembly sheet 1.

Next, a description is given to the method for producing the wiredcircuit board assembly sheet 1 with reference to FIGS. 6 and 7.

As shown in FIG. 6( a), the metal supporting board 45 is prepared. Themetal supporting board 45 is made of a metal thin plate for forming themetal supporting layer 19 and formed in the shape of a generallyrectangular flat plate when viewed in plan view, as shown in FIG. 1.

Then, as shown in FIG. 6( b), the plurality of insulating base layers 16are formed simultaneously in a pattern corresponding to the individualwired circuit boards 2 and the individual distinguishing marks 3 on themetal supporting board 45.

In the formation of each of the insulating base layers 16, a solution(varnish) of a synthetic resin is coated in the foregoing pattern on thesurface of the metal supporting board 45, dried, and then heated to becured as necessary. In the case of using a photosensitive syntheticresin, a photosensitive synthetic resin is coated over the entiresurface of the metal supporting board 45. Thereafter, the photosensitivesynthetic resin is exposed to light, developed to provide the foregoingpattern, and then heated to be cured as necessary. The formation of theinsulating base layer 16 is not limited to the method described above.For example, it is also possible to, e.g., preliminarily form asynthetic resin into a film in the foregoing pattern and then bond thefilm onto the surface of the metal supporting board 45 via a knownadhesive layer.

Then, as shown in FIG. 6( c), the conductive pattern 17 is formed on theinsulating base layer 16 of each of the wired circuit boards 2, whilethe mark formation portion 34 is formed simultaneously on the insulatingbase layer 16 of each of the distinguishing marks 3 in the patterncorresponding thereto. To form each of the conductive patterns 17 andthe mark formation portions 34, a known patterning method such as anadditive method or a subtractive method is used, or preferably theadditive method is used.

Then, as shown in FIG. 6( d), the insulating cover layers 18 are formedover the respective surfaces of the insulating base layers 16 to coverthe respective conductive patterns 17 of the wired circuit boards 2.

More specifically, in each of the wired circuit boards 2, the insulatingcover layer 18 is formed on the insulating base layer 16 to expose thefirst terminal portion 14 and the second terminal portions 15. In eachof the distinguishing marks 3, the insulating cover layer 18 issimultaneously formed on the insulating base layer 16 to cover the markformation portion 34 and expose the non-defective mark 38.

In the formation of each of the insulating cover layers 18, a solutionof the synthetic resins described above is coated in the foregoingpattern, dried, and then heated to be cured as necessary. Alternatively,a photosensitive synthetic resin is coated entirely over the metalsupporting board 45 and the insulating base layer 16, exposed to light,developed to provide the foregoing pattern, and, then heated to be curedas necessary. The formation of the insulating cover layer 18 is notlimited to the method described above. It is also possible to, e.g.,preliminarily form a synthetic resin into a film in the foregoingpattern and then bond the film onto the insulating base layer 16 of eachof the wired circuit boards 2 and onto the insulating base layer 16 ofeach of the distinguishing marks 3 each via a known adhesive layer.

Then, as shown in FIGS. 7( e) to 7(g), the opening 29 of each of thedistinguishing marks 3 for the wired circuit boards 2 and each of theclearance grooves 27 of the supporting sheet 4 are formed simultaneouslyby cutting out the metal supporting board 45.

To form the opening 29 of each of the distinguishing marks 3 and each ofthe clearance grooves 27 of the supporting sheet 4, an etching resist 46is formed first over the entire top surface of the wired circuit boardassembly sheet 1 in the midway of production process, while the etchingresist 46 is formed in a pattern reverse to the pattern in which theopening 29 of each of the distinguishing marks 3 and each of theclearance grooves 27 of the supporting sheet 4 on the back surface ofthe wired circuit board assembly sheet 1 are formed, as shown in FIG. 7(e).

The etching resist 46 is formed in the foregoing pattern by a knownphoto-process in which, e.g., a dry film photoresist is laminated overthe entire top and back surfaces of the wired circuit board assemblysheet 1 in the midway of production process, exposed to light, and thendeveloped.

Then, as shown in FIG. 7( f), the metal supporting board 45 exposed fromthe etching resist 46 is etched away. The etching is performed by a wetetching (chemical etching) method in which, e.g., an aqueous ferricchloride solution or the like as an etching solution is sprayed onto themetal supporting board 45 or the metal supporting board 45 in the midwayof production process is dipped in the etching solution.

Then, as shown in FIG. 7( g), the etching resist 46 is removed byetching or stripping it away.

In this manner, the opening 29 of each of the distinguishing marks 3 andeach of the clearance grooves 27 of the supporting sheet 4 can be formedsimultaneously and the wired circuit board assembly sheet 1 formed witheach of the wired circuit boards 2, each of the distinguishing marks 3,and the supporting sheet 4 can be obtained.

Then, a metal plating layer made of gold or the like not shown is formedon the surfaces of the first terminal portion 14, the second terminalportions 15, and the non-defective mark 38.

Thereafter, in the wired circuit board assembly sheet 1 thus obtained,defectiveness is determined by examining whether or not the conductivepattern 17 of the respective wired circuit board 2 contains a brokenwire. The presence or absence of a broken wire in the conductive pattern17 is determined by optically detecting the contrast between theconductive pattern 17 and the insulating cover layer 18.

Then, the wired circuit board 2 in which a broken wire is detected inthe conductive pattern 17 is distinguished as defective. Of the pair ofdistinguishing marks 3 adjacent to the wired circuit board 2 that isdistinguished as defective, the one having the indication region 44 ofwhich the indication direction indicates the wired circuit board 2 isidentified through visual observation and the removal portion 31 of thedistinguishing mark 3 is removed. For example, when the one wiredcircuit board 2 a in the pair of wired circuit boards 2 is determined asdefective, the one distinguishing mark 3 a in the pair of distinguishingmarks 3 adjacent to the one wired circuit board 2 a having theindication region 44 of which the indication direction indicates the onewired circuit board 2 a is identified through visual observation and theremoval portion 31 a of the one distinguishing mark 3 a is removed. Ofthe pair of wired circuit boards 2, when both of the one wired circuitboard 2 a and the other wired circuit board 2 b are determined asdefective, the removal portion 31 a of the distinguishing mark 3 a andthe removal portion 31 b of the distinguishing mark 3 b are bothremoved. Thus, in this case, both of the removal portions 31 of thedistinguishing marks 3 adjacent to each other are removed.

The removal portion 31 is removed by punching using a punch, by stampingusing a male or female stamping die or by vacuuming using a vacuumsuction device.

In this manner, the wired circuit board 2 that is defective can beidentified by visually observing the indication direction of theindication region 44 of the distinguishing mark 3 from which the removalportion 31 is removed. For example, when the removal portion 31 a of theone distinguishing mark 3 a is removed, it can be recognized that theone wired circuit board 2 a is defective by visually observing theindication direction of the indication region 44 a thereof.

In the wired circuit board 2 determined as non-defective, the removalportion 31 of the corresponding distinguishing mark 3 remains so that itis possible to recognize that the wired circuit board 2 is non-defectiveby visually observing the non-defective mark 38 of the removal portion31.

Thus, in the wired circuit board assembly sheet 1, each of thedistinguishing marks 3 for distinguishing defectiveness of the wiredcircuit boards 2 is formed with the indication region 44. When thedistinguishing marks 3 are formed in the wired circuit board assemblysheet 1, the one distinguishing mark 3 a is disposed such that theindication direction of the indication region 44 a thereof is directedtoward the one wired circuit board 2 a and the other distinguishing mark3 b is disposed such that the indication region 44 b thereof is directedtoward the other wired circuit board 2 b. This makes it possible todistinctly represent the correspondence between each of thedistinguishing marks 3 and each of the wired circuit boards 2. As aresult, even when the density of the wired circuit boards 2 in the wiredcircuit board assembly sheet 1 is high and the pair of wired circuitboards 2 are adjacent to either the one distinguishing mark 3 a or theother distinguishing mark 3 b, or the one distinguishing mark 3 a isadjacent to the other distinguishing mark 3 b, the wired circuit board 2corresponding to each of the distinguishing marks 3 can be easilyidentified. Therefore, it is possible to reliably remove the removalportion 31 for the wired circuit board 2 determined as defective. Inaddition, it is possible to prevent the removal portion 31 of the wiredcircuit board 2 determined as non-defective from being erroneouslyremoved.

Each of the distinguishing marks 3 has a non-point-symmetrical shape,i.e., a generally triangular shape having curved angles. This makes itpossible to prevent the indication direction of the indication region 44and a direction (designated as the quasi-indication direction) which maypossibly be the indication direction of the region (indicated as aquasi-indication region 47 by the broken arrow in FIG. 5) surroundingthe vertices other than the indication vertex 30 identically to theindication region 44 from overlapping on the same straight line. Inother words, it is possible to prevent the quasi-indication direction ofthe one distinguishing mark 3 a from facing downward in the verticaldirection of FIG. 1. As a result, it is less likely to misidentify theone wired circuit board 2 a corresponding to the one distinguishing mark3 a from being as the other wired circuit board 2 b and it is possibleto easily and reliably identify the one wired circuit board 2 acorresponding to the one distinguishing mark 3 a.

Since the indication region 44 has a shape which is tapered toward theindication direction indicating the specified wired circuit board 2, theindication direction of the indication region 44 can be distinctlyrepresented and the wired circuit board 2 corresponding to each of thedistinguishing marks 3 can be easily identified.

Since the distinguishing mark 3, more specifically the outer frameportion 32, has a generally triangular shape having an odd number ofangles, it is possible to use the part including an arbitrary angle asthe indication region 44 and indicate the specified wired circuit board2 with the indication region 44. In addition, because the distinguishingmark 3 has a generally simple triangular shape, the distinguishing mark3 can be formed easily.

In the wired circuit board assembly sheet 1, the one distinguishing mark3 a and the other distinguishing mark 3 b are arranged in mutuallyspaced-apart relation in the lateral direction of FIG. 1 and theindication directions of the respective indication regions 44 of thedistinguishing marks 3 are vertically reverse to each other. That is,the indication direction of the indication region 44 a of the onedistinguishing mark 3 a faces upward in the vertical direction of FIG.1, while the indication direction of the indication region 44 b of theother distinguishing mark 3 b faces downward in the vertical directionof FIG. 1. As a result, when the wired circuit board 2 corresponding toeach of the distinguishing marks 3 is identified, it is less likely toconfuse the corresponding wired circuit board 2 with another wiredcircuit board 2 and it is possible to easily identify the wired circuitboard 2 corresponding to each of the distinguishing marks 3.

In addition, the openings 29 are formed in the portions (distinguishingmark formation regions 28) of the supporting sheet 4 provided with thedistinguishing marks 3 and each of the distinguishing marks 3 comprisesthe removal portion 31 for indicating defectiveness of the correspondingwired circuit board 2 and the joint portions 33 made of a resin forcoupling the removal portion 31 to the supporting sheet 4. As a result,when the removal portion 31 which shows that the wired circuit board 2is either defective or non-defective is removed, the removal portion 31can be easily removed from the supporting sheet 4 in the opening 29 bycutting the joint portions 33. Because the joint portions 33 are made ofa resin, there is no production of metal powder or the like even whenthe joint portions 33 are cut so that the wired circuit board 2 isallowed to retain its excellent electric characteristics. Even whenpunching is performed with a stamping die, the abrasion of the stampingdie can be reduced. As a result, it is possible to easily and reliablyremove the removal portion 31 to provide the wired circuit board 2 withhigh connection reliability.

Although the distinguishing mark 3 is formed in a generallyequilaterally triangular shape when viewed in plan view in thedescription given above, the shape of the distinguishing mark 3 is notparticularly limited as long as the part which can serve as theindication region 44 for indicating the specified wired circuit board 2is formed. The distinguishing mark 3 can be formed in, e.g., anequilaterally pentagonal shape when viewed in plan view as shown in FIG.8( a), a generally pentagonal shape (in the shape of a home plate) whenviewed in plan view as shown in FIG. 8( b), an equilaterally heptagonalshape when viewed in plan view as shown in FIG. 8( c), a generallyheptagonal shape when viewed in plan view as shown in FIG. 8( d), anarrow-like shape when viewed in plan view as shown in FIG. 9( e), aconvex shape when viewed in plan view as shown in FIG. 9( f), asectorial shape when viewed in plan view as shown in FIG. 9( g), or thelike.

Although the removal portion 31 is removed when the wired circuit board2 is defective in the description given above, the removal portion 31can also be removed when the wired circuit board 2 is non-defective.

In this case, when the wired circuit board 2 is determined as defective,the removal portion 31 of the distinguishing mark 3 corresponding to thewired circuit board 2 remains and the remaining removal portion 31confirms that the determination of the wired circuit board 2 isdefective.

Although the distinguishing mark 3 is provided with the removal portion31 and the removal portion 31 is removed when the corresponding wiredcircuit board 2 is determined as defective (or non-defective) in theembodiments described above, the distinguishing mark 3 need notparticularly be provided. It is also possible to, e.g., form thedistinguishing mark 3 in a shape in which the indication region 44 isformed after the inspection and form the indication region 44 as adepressed portion in the wired circuit board assembly sheet 1 using apunch or the like or form the indication region 44 as a mark on thewired circuit board assembly sheet 1 with ink.

While the illustrative embodiments of the present invention are providedin the above description, such is for illustrative purpose only and itis not to be construed limitative. Modification and variation of thepresent invention that will be obvious to those skilled in the art is tobe covered by the following claims.

1. A wired circuit board assembly sheet comprising: a plurality of wiredcircuit boards; distinguishing marks for distinguishing defectiveness ofthe wired circuit boards; and a supporting sheet for supporting theplurality of wired circuit boards and the distinguishing marks, whereineach of the distinguishing marks comprises an indication portion forindicating a specified wired circuit board, wherein the distinguishingmarks are not attached to the wired circuit boards; wherein each of thedistinguishing marks is provided on the supporting sheet in aspaced-apart relation from the specified wired circuit boardcorresponding to said each distinguishing mark, and the indicationportion indicates the specified wired circuit board from external of thespecified wired circuit board; and wherein the indication portion has ashape tapered toward an indication direction indicating the specifiedwired circuit board.
 2. The wired circuit board assembly sheet accordingto claim 1, wherein each of the distinguishing marks is formed in anon-point-symmetrical shape.
 3. (canceled)
 4. The wired circuit boardassembly sheet according to claim 1, wherein each of the distinguishingmarks has a generally polygonal shape having an odd number of angles. 5.The wired circuit board assembly sheet according to claim 1, wherein thedistinguishing marks are arranged in mutually adjacent relation; andwherein the indication portions of the distinguishing marks are arrangedin adjacent relation having respective indication directions differentfrom each other.
 6. (canceled)
 7. A wired circuit board assembly sheetcomprising: a plurality of wired circuit boards; distinguishing marksfor distinguishing defectiveness of the wired circuit boards; and asupporting sheet for supporting the plurality of wired circuit boardsand the distinguishing marks, wherein each of the distinguishing markscomprises an indication portion for indicating a specified wired circuitboard; wherein the distinguishing marks are not attached to the wiredcircuit boards; wherein each of the distinguishing marks is provided onthe supporting sheet in a spaced-apart relation from the specified wiredcircuit board corresponding to said each distinguishing mark, and theindication portion indicates the specified wired circuit board fromexternal of the specified wired circuit board; and wherein each of thedistinguishing marks has a generally polygonal shape having an oddnumber of angles.
 8. A wired circuit board assembly sheet comprising: aplurality of wired circuit boards; distinguishing marks fordistinguishing defectiveness of the wired circuit boards; and asupporting sheet for supporting the plurality of wired circuit boardsand the distinguishing marks, wherein each of the distinguishing markscomprises an indication portion for indicating a specified wired circuitboard; wherein the distinguishing marks are not attached to the wiredcircuit boards; wherein each of the distinguishing marks is provided onthe supporting sheet in a spaced-apart relation from the specified wiredcircuit board corresponding to said each distinguishing mark, and theindication portion indicates the specified wired circuit board fromexternal of the specified wired circuit board; and wherein each of thedistinguishing marks has a convex shape when viewed in plan view.